Round red itchy circles

Our old boy has been going through bouts of itchy red circles all over his body. These areas lose fur and are scabby in the middle. It seems to get worse when the weather begins to warm up (maybe pollen?). He has been tested for allergies and he is allergic to just about everything. We have to cook his food specifically to avoid any problems as there is no ready made dog food that he can eat. We don't give him store bought treats or people food and he is treated for fleas on a regular basis (not allergic to fleas).
Problem went away for about a year but has now returned with a vengeance. We've been to eight different vets and only one thought it was allergies one said a thyroid problem and two said to give him Benadryl. The rest really didn't have any good answers . He has been tested for parasites also but none found.
He has problems with fowl, corn, oatmeal, venison, fly spit, white potato, peas, house dust, mites, certain weeds and grasses, oak, cat fur, barley etc.. He also licks his paws constantly, doesn't scratch, vomits on occasion, has good stools and loves to eat grass but we watch him like a hawk when he's outside. Our yard does not have the grasses he is allergic to.
At this point, we are totally stumped and have tried just about everything. Is there a way to make him feel more comfortable if we can't figure this out? Thanks for any ideas!

The most common reasons for circular areas of hairloss and scabs in dogs are skin infection due to bacterial infection (most common), demodex mites or fungal (ringworm) infection. When faced with a case with these symptoms, I first perform skin scrapings to evaluate for infection and parasites, +/- ringworm culture. If the scrapings show bacteria, then I treat with a minimum 3 week course of oral antibiotics plus antibacterial shampoos 1-2 times weekly. If infection resolves then recurs, then there has to be an underlying cause. The most common underlying causes are allergies (food allergy or pollen/dust allergies) and hormonal diseases (low thyroid or Cushing's disease). If symptoms begin later in life, food allergy and hormonal diseases are most common (pollen and dust allergies usually start 6mo - 5 yrs of age). So in older dogs I start with full labwork and thyroid profile. If the thyroid levels are low then that is treated with lifelong medication. If liver enzymes are elevated and there are other consistent clinical signs of Cushing's disease (excess adrenal steroid production), then I test for Cushing's. If all labwork is normal, then I investigate possible food allergy with a hypoallergenic diet trial, consisting of one protein and one carbohydrate that the dog has never had before, and no treats, table scraps, rawhides, milkbones, chewable supplements etc. for 8 weeks. Natural Balance makes a fish and sweet potato diet which you can try. Blood allergy testing for food is not accurate in dogs. If symptoms persist or recur despite the strict hypoallergenic diet, then I consider allergy testing for pollen/dust allergies and desensitization injections. Since you have gone to numerous veterinarians with no real answer, I recommend consulting with a veterinary dermatologist--you can find one in your area at www.acvd.org.
Good luck,
Kimberly Coyner, DVM DACVD
www.dermvetvegas.com

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